In recent years the number of cases of Alzheimer's disease has noticeably increased, and according to the forecast of scientists, the number of people suffering from this disease may reach 50 million in near decades.
Alzheimer's disease is one of most widely spread forms of acquired dementia that affects the population of developed countries. In the USA alone the number of people suffering from this disease is about 4.5 million, and it is very difficult to diagnose this disease in its early stage.
Alzheimer's disease is a degenerative disease of the brain that manifests itself in progressive loss of memory and intellect and, in the long run, leads to complete degradation of personality. Until the present time, etiology of this disease has not been completely known, and it is not infrequent that this disease has an inheritable nature.
In the Alzheimer's disease, main structural changes are revealed in the surface structures of the brain (cerebral brain cortex) and in the hippocampus, which is located in the depth of the hemispheres and plays an important role in memory and processes of memorization. Microscopic observations show that these changes are characterized by the presence of so-called neurofibrillar glomerules that consist of pathologically changed neurons (nerve cells) that contain specific fibrillar proteins and neuritic plaques that comprise deposits of amyloids, i.e., protein-hydrocarbon complexes, in an intercellular space of the brain. At the same time, one can observe a reduction of the capillary bloodstream in the frontoparietal part with development of multiple arteriovenous shunts.
At the present time Alzheimer's diseases is treated mainly by symptomatic methods based on introduction of acetylcholine and psycotropic preparations designed for correcting behavioristic deviations.
At the present time, Alzheimer's disease is treated mainly on the basis of symptomatic methods relating to introduction of acetylcholine and psycotropic preparations designed for correcting behavioristic deviations. For example, an article by Jacobsen, F. M. and Comas-Diaz, L. in (http://cat.inist.fr/?aModele=afficheN&cpsidt=1997195) describes the use of donepezil for treating psychotropic-induced memory loss. Donepezil is an acetylcholinesterase inhibitor marketed for treatment of memory loss and behavioral deterioration associated with the acetylcholine deficit of Alzheimer's disease. The authors investigated the utility and tolerability of donepezil in nongeriatric-affective illness for treatment of psychotropic-induced memory loss, dry mouth, and constipation. Nondemented outpatients with stabilized DSM-IV-affective illness took 5 mg/day of donepezil for three weeks and then increased to 10 mg/day in open trials. Self-rating scales of target symptoms were completed by patients before and three to four weeks after starting each dose. Patients who chose to continue donepezil therapy returned for clinical monitoring every four to eight weeks. Results showed that 11 women and 11 men (mean±SD age=45.4±8.5 years) completed donepezil trials. Nineteen patients with memory loss rated improvement while taking 5 mg/day of donepezil (p<0.001); subsequently, six patients rated further improvement with
10 mg/day (p=0.057). Donepezil, 5 mg/day, also reduced ratings of dry mouth (N=16; p<0.001) and constipation (N=11; p<0.05). Side effects included insomnia, nausea, vomiting, and diarrhea; surprisingly, two bipolar patients became manic within hours of starting donepezil. Sixteen patients (72%) continued donepezil for an average of seven months. Consideration of family histories suggested that donepezil response in affective illness may be an early indicator of vulnerability to dementia of the Alzheimer's type.
However, even though donepezil can reduce memory loss, dry mouth, and constipation in nongeriatric-affective patients, the authors, themselves, state that use of this preparation may trigger mania and may have other side effects.
Physicians at the University of California, San Diego (UCSD) School of Medicine have surgically implanted genetically modified tissue into the brain of an Alzheimer's patient. This launches the first phase of an experimental gene therapy protocol for Alzheimer's disease. The 11-hour procedure was performed at UCSD's John M. and Sally B. Thornton Hospital in La Jolla on a 60-year-old woman in the early stages of Alzheimer's disease. The authors reported that the patient was recovering well. The authors also stated that the proposed gene therapy is not expected to cure Alzheimer's disease, but they hope that it might protect and even restore certain brain cells and alleviate some symptoms, such as short-term memory loss, for a period that could last a few years. This procedure targets a class of cells located deep within the brain in an area called the cholinergic system, important for supporting memory and cognitive function.
The cholinergic system profoundly degenerates in the course of Alzheimer's disease. These cells have been shown to respond to the implanted genetically modified tissue in primate studies, and the researchers hope that preventing extensive loss of these cells may slow intellectual decline seen in Alzheimer's patients.
Also known in the art are some other surgical methods for treating Alzheimer's disease. For example, neurologists at Emory University (Atlanta, Ga., USA) are studying a possible new treatment for Alzheimer's disease using a device called the COGNIShunt, which is designed to drain cerebrospinal fluid (CSF) from the skull into the abdominal cavity. Doctors are hopeful that by reducing the buildup of CSF around the brain, this device will help to stabilize the disease.
CSF is the fluid that fills the empty spaces around the brain and spinal cord. The body naturally produces, absorbs, drains, and replenishes the fluid; however, with age, the replenishing process slows. Shunting has long been used as treatment for hydrocephalus, a condition in which an abnormal accumulation of CSF causes neurological problems, including dementia, problems walking, and incontinence. In the Emory study, surgeons surgically implant the COGNIShunt into a normal cavity, or ventricle, in the brain. Then they tunnel a tube through the neck and into the abdominal cavity for proper drainage. This procedure is a relatively short and common procedure that usually requires a one- to two-day hospital stay. However, the results of this study are yet unknown, and there are some risks associated with implanting the device. The risks include infections, bleeding, or a chance that the shunt or tube could stop working.
On the other hand, known in the art is the use of endovascular catheters for internal treatment of patients suffering from vascular disorders. For example, U.S. Pat. No. 7,048,719 issued in 2006 to Richard R. Monetti discloses the use of endovascular microcatheters to deliver embolic devices useful in occluding blood flow through a patient's vasculature. Blood flow occlusion may be useful in controlling vascular bleeding, controlling blood supply to tumors, and to occlude vascular aneurysms, including intracranial aneurysms. Microcatheters can be used when treating blood vessels of extremely small size, for example, intracranial blood vessels. In particular, the aforementioned patent discloses a resheathing apparatus useable to resheath an elongate member such as a catheter, embolization member deployment apparatus, or other elongate structure. The resheathing apparatus comprises a guide that has one or more lumens extending from the proximal end to the distal end of the guide. The guide also may have a branch extending away from the lumen of the guide. The branch is structured to fit in a sheath that may be disposed around the deployment structure. The branch is oriented to direct the sheath onto or off the deployment structure, depending on whether the deployment structure is to be resheathed or desheathed, respectively. The resheathing apparatus may also comprise a guide tube disposed over the branch of the guide to facilitate movement of the sheath over the branch of the guide and over the deployment structure.
The endovascular catheter of the type shown in the above patent can be used for angioplasty and for delivery of embolic devices useful in occluding blood flow through a patient's vasculature. Blood flow occlusion may be useful in controlling vascular bleeding, controlling blood supply to tumors, and to occlude vascular aneurysms, including intracranial aneurysms. Microcatheters can be employed when treating blood vessels of extremely small size, for example, intracranial blood vessels.
In spite of all known attempts aimed at treating Alzheimer's disease and attempts as described above, the inventor herein is not aware of surgical methods and devices for treating this disease based on restoring surrounding brain tissue by improving microcirculation and collateral bloodstreams in the brain.